1. Field of the Invention
The present invention relates to an apparatus for opening and closing an air flap for a vehicle which is moved up and down to permit external air to flow into a cooling module only when a coolant temperature is within a range of overheating after an engine has warmed up, and to prevent air from flowing into the cooling module except when the coolant temperature is within the range of overheating.
2. Description of Related Art
Generally, a water-cooling type cooling device includes a water jacket which surrounds a cylinder and a combustion chamber, a water pump which forces water to flow into the cylinder, a radiator which transmits heat from high-temperature coolant to the atmosphere so as to cool the coolant, a fan which helps the radiator to circulate the air, and a thermostat which is used to rapidly regulate the temperature of the coolant immediately after starting an engine.
The operation of the water-cooling type cooling device will now be described. That is, a coolant passage is formed in each of a cylinder block and a cylinder head, so that water flows through the coolant passage to cool respective parts of the engine. The coolant used to cool the cylinder block is forcibly fed from a radiator hose to the radiator by the water pump which is driven by a crank shaft pulley. The coolant fed to the radiator dissipates heat, and thereafter is returned to the engine again so as to cool it.
The radiator is a kind of tank which has a large heat dissipating area and may contain a large quantity of water therein. The radiator includes a pipe through which water flows and fins which are in contact with the air, and is formed to have a large heat dissipating area so as to dissipate as much heat as is possible to the atmosphere. In order to separate the radiator from the outside of a vehicle and provide a good appearance to the vehicle, a radiator grill is mounted to a predetermined portion of a front bumper of the vehicle.
The radiator grill allows a predetermined amount of air to flow through the front of the vehicle, in addition to physically protecting the radiator from impurities which enter the front of the vehicle along with the air.
However, the radiator grill is problematic in that it is always open, so that external air may undesirably flow into a cooling module and thereby cool it before the engine has warmed up. Consequently, the engine is warmed up slower.
Further, a wind generated while the vehicle is being driven flows through the radiator grill which is always open into an engine room, thus causing the deterioration of aerodynamic performance.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.